Targeting aneurysm disease by modulating phagocytosis pathways

ABSTRACT

In the methods of the invention, an agent that increases phagocytosis and/or efferocytosis of cellular components of coronary plaque is administered to the subject in a dose and for a period of time effective to stabilize, prevent or reduce aneurysm disease in the individual.

CROSS REFERENCE

This application is a Continuation and claims benefit of 371 applicationNo. 15/510,591, filed Mar. 10, 2017, which claims benefit of PCTApplication No. PCT/US2015/049150, filed Sep. 9, 2015, which claimsbenefit of U.S. Provisional Patent Application No. 62/050,664, filedSep. 15, 2014, which applications are incorporated herein by referencein their entirety.

FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

This invention was made with Government support under contract HL103605awarded by the National Institutes of Health. The Government has certainrights in the invention.

BACKGROUND OF THE INVENTION

Serious vascular defect can result when an area of weakened vessel wallcauses a bulge, or bubble, to protrude out in a radial direction fromthe vessel. Such aneurysms can occur at various positions within thevasculature. Abdominal aortic aneurysms most often develop in therelatively long segment of aorta between the renal arteries and thebifurcation of the aorta into the right and left iliac arteries.Abdominal aortic aneurysms progressively enlarge at variable andunpredictable rates, and as they do, the involved aneurysm wall becomesweaker and thinner, and eventually ruptures. Rupture is relativelyuncommon in abdominal aortic aneurysms less than five centimetersmaximum transverse diameter, but the risk increases with increasingsize. Rupture of abdominal aortic aneurysms has been responsible forapproximately 15,000 deaths per year in the United States.

Endovascular repair of aortic aneurysms has been shown to be effectivein preventing rupture of abdominal and thoracic aortic aneurysms and hasreduced morbidity compared to open surgical repair. Consequently,endovascular repair is now extended to many patients who were notconsidered to be candidates for aneurysm repair in the past. However,despite the clear benefits of endovascular surgery in the earlyperi-operative period, there are significant concerns regarding thelong-term stability and durability of endovascular repair. Despite thesesurgical advances, aneurysm disease remains a leading killer and nomedical therapies have been convincingly proven to slow aneurysmprogression or prevent rupture.

Methods for treating and preventing aneurysm disease are of greatinterest and are addressed by the present invention.

PUBLICATIONS

Patent publications relating to aortic aneurysms include, inter alia,USRE38146 “Method and apparatus for bilateral intra-aortic bypass”; U.S.Pat. No. 5,578,072, “Aortic graft and apparatus for repairing anabdominal aortic aneurysm”; U.S. Pat. No. 5,522,880, “Method forrepairing an abdominal aortic aneurysm”; U.S. Pat. No. 5,489,295,“Endovascular graft having bifurcation and apparatus and method fordeploying the same”; U.S. Pat. No. 6,475,466, “Methods for treatingendoleaks during endovascular repair of abdominal aortic aneurysms”;U.S. Pat. No. 6,409,756, “Endovascular aortic graft”; U.S. Pat. No.6,767,359 “Prosthesis for the repair of thoracic or abdominal aorticaneurysms and method therefore”; U.S. Pat. No. 5,643,208, “Balloondevice for use in repairing an abdominal aortic aneurysm”; U.S. Pat. No.4,577,631, “Aneurysm repair apparatus and method”; U.S. Pat. No.7,112,217, “Biluminal endovascular graft system”; U.S. Pat. No.7,004,964, “Apparatus and method for deployment of an endoluminaldevice”; U.S. Pat. No. 6,814,748, “Intraluminal grafting system”; U.S.Pat. No. 6,303,100, “Methods for inhibiting the formation of potentialendoleaks associated with endovascular repair of abdominal aorticaneurysms”; U.S. Pat. No. 5,681,346, “Expandable stent formingprojecting barbs and method for deploying”; U.S. Pat. No. 5,207,695,“Aortic graft, implantation device, and method for repairing aorticaneurysm”; U.S. Pat. No. 4,313,231, “Vascular prosthesis”.

Leeper et al. (2013) Arterioscler Thromb Vasc Biol. 2013; 33:e1-e10,herein specifically incorporated by reference, discusses how loss ofCDKN2B promotes p53-dependent smooth muscle cell apoptosis and aneurysm.Co-pending patent application 61/879,562, herein specificallyincorporated by reference, discusses the role of modulatingefferocytosis in atherosclerotic disease.

SUMMARY OF THE INVENTION

Methods are provided for modulation of efferocytosis/phagocytosispathways (referred to herein as EP pathways) for treatment and/orprevention of aneurysm disease in a subject. By administering an agentthat targets the EP pathway including CDKN2B, calreticulin, and CD47,the EP pathway can be normalized and reduce risk of aneurysm. Aneurysmdisease as used herein includes without limitation abdominal aorticaneurysms (AAA disease), thoracic aortic aneurysm, intracranialaneurysms (berry aneurysms), post stenotic dilatation, aorticdissection, etc. Abdominal aortic aneurysms are of particular interest.

In some embodiments, the subject is homozygous or heterozygous for a9p21 risk allele. In some such embodiments the methods include genetictesting of the subject for the presence of a 9p21 risk allele. In othersuch embodiments the subject has been previously diagnosed for thepresence of a 9p21 risk allele. Such diagnostic methods may include,without limitation, analyzing a sample of genomic DNA from theindividual for the presence of sequences of human chromosome 9p21associated risk of CAD, including SNPs associated with the risk locus.

In some embodiments the subject has been diagnosed with an aneurysm,e.g. an aneurysm greater than the normal diameter of the artery. Anaortic aneurysm greater than the normal diameter may be, for examplegreater than about 2 cm diameter of the aorta, and may be less thanabout the size of an aneurysm for which surgery is indicated, e.g. lessthan about 6 cm diameter, less than about 5.5 cm diameter, less thanabout 5 cm diameter. Treatment may be initiated when an aneurysm,including without limitation an aortic aneurysm, is greater than about 2cm, greater than about 2.5 cm, greater than about 3 cm, greater thanabout 3.5 cm, greater than about 4 cm, greater than about 4.5 cm, andmay be less than about 6 cm, less than about 5.5 cm, less than about 5cm diameter. The methods of the invention may also include monitoring aknown aneurysm through imaging techniques during treatment for changesin size.

In the methods of the invention, an EP agent that increases phagocytosisof components of the diseased blood vessel, including macrophagephagocytosis and efferocytosis of apoptotic smooth muscle cells, isadministered to the subject in a dose and for a period of time effectiveto stabilize, prevent or reduce aneurysm disease in the individual.Molecular targets for increasing efferocytosis and macrophagephagocytosis include, without limitation, agents that activate orincrease expression of CDKN2B or Retinoblastoma (Rb), or decrease theexpression of E2F4; agents that increase activity or expression ofcalreticulin; agents that block the interaction of CD47 and SIRPα; andthe like. In other embodiments the agent enhances expression of CDKN2Bin cardiovascular cells, including, for example, smooth muscle cells.Such agents may include, for example, palbociclib;5-aza-2′-deoxycytidine in the absence or presence of phenylbutyrate;etc.

In some embodiments, the agent that increases EP pathway activityreduces the interaction of CD47 and SIRPα, which agent may be referredto herein as an anti-CD47 agent. In some embodiments such agents do notinterfere with the interaction between CD47 and thrombospondin.Preferred anti-CD47 agents include soluble SIRPα, for example a highaffinity soluble SIRPα; anti-CD47 antibodies, anti-SIRPα antibodies,etc.

In some embodiments the EP agent mimics or enhances calreticulin.Calreticulin “mimetics” and “agonists” include molecules that functionsimilarly to, or potentiate, CRT by binding and activating LRP receptor.Molecules useful as CRT mimetics include derivatives, variants, andbiologically active fragments of naturally occurring CRT. Moleculesuseful as agonists include antibodies and other agents that act toenhance the pro-phagocytic activity of CRT.

Another aspect of the present invention relates to the use of an EPstimulating agent in the manufacture of a medicament to stabilize,prevent or reduce aneurysm disease, wherein the medicament isadministered to an individual having or at risk of having aneurysmdisease.

Still another aspect of the present invention provides a kit tostabilize, prevent or reduce aneurysm disease. The kit includes anphagocytosis stimulating agent, in an amount sufficient to stabilize,prevent or reduce aneurysm disease. The kit may also include reagentsfor genotyping at human chromosome 9p21, including alleles of rs10757278and rs1333049. The kit may also instructions for use, reagents formonitoring aneurysm disease, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in conjunction with the accompanying drawings. The patent orapplication file contains at least one drawing executed in color. Copiesof this patent or patent application publication with color drawing(s)will be provided by the Office upon request and payment of the necessaryfee. It is emphasized that, according to common practice, the variousfeatures of the drawings are not to-scale. On the contrary, thedimensions of the various features are arbitrarily expanded or reducedfor clarity. Included in the drawings are the following figures.

FIG. 1. Overview of atherosclerosis prevention study, showing timelinefor anti-Cd47 Ab injection, blood pressure measurement, and high fatdiet administration (top). Blood pressure changes over time during thetreatment period (bottom).

FIG. 2. Representative explanted aortas from control Ab treated mice(IgG) reveal a high incidence of aneurysms after angiotensin infusion.Inset reveals aneurysm scoring system (0-4, with 0 having no aneurysm,and 4 representing a mouse which died of aortic rupture during thetreatment period).

FIG. 3. Representative explanted aortas from antiCD47 Ab treated mice(MIAP410) reveal a low incidence of aneurysms after angiotensininfusion. Inset reveals aneurysm scoring system (0-4, with 0 having noaneurysm, and 4 representing a mouse which died of aortic rupture duringthe treatment period).

FIG. 4. Comparison of control Ab (IgG) and antiCD47 Ab (MIAP410) treatedmice reveals that antiCD47 Ab treatment prevents aneurysm development(Top Left), reduces aneurysm size (Top Right) and reduces aneurysmseverity (Bottom, scale as in preceding panels). All differencessignificant with p value <0.01.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to methods of treating a subject foraneurysm disease, by administering an agent that increases phagocytosisof diseased vascular tissue, including the efferocytosis and/orphagocytosis of apoptotic smooth muscle cells, which may herein bereferred to as an EP agent. In some embodiments, the subject ishomozygous or heterozygous for a 9p21 risk allele. In some embodiments,the EP agent provides for one or more of the following activities:reduces the binding of CD47 to SIRPα; increases or mimics the activityof calreticulin, including binding of calreticulin to LRP; or increasesexpression of CDKN2B.

Aneurysm is a dilation in the wall of an artery, such as the aorta.Aneurysms can develop anywhere along the aorta, including the abdominalaorta and thoracic aorta. Aneurysms can also develop in poplitealarteries, femoral arteries, carotid arteries, cerebral arteries, andcoronary arteries. Aneurysms may be saccular or fusiform. Abdominalaortic aneurysms are a major manifestation of atherosclerosis, a diseaseprocess that affects the entire vascular system. Thrombus often developin the aneurysm because blood flow inside the aneurysm is sluggish. Theclot may extend along the entire wall of the aneurysm.

The presence of aneurysms can be difficult to diagnose, as many peoplewith aneurysms have no symptoms and are diagnosed by chance when aroutine physical examination or an imaging procedure is done. Usually,ultrasonography can clearly show the size of an aneurysm. If an aneurysmis detected, ultrasonography may be repeated every few months todetermine if and how quickly the aneurysm is enlarging. Computedtomography (CT) of the abdomen, particularly if done after a radiopaquedye is injected intravenously, can determine the size and shape of ananeurysm more accurately than ultrasonography. Magnetic resonanceimaging (MRI) is also accurate.

Aneurysms that are wider than about 5 cm may rupture, and are oftentreated by inserting a synthetic graft to repair the aneurysm. Typicallywith endovascular stent grafting a catheter containing the stent-graftis guided over the wire and positioned inside the aneurysm. Then thestent-graft is opened, forming a stable channel for blood flow. If theiliac arteries are involved, the graft must be extended to include them.If the aneurysm extends above the renal arteries, the renal arteriesmust be reimplanted into the graft, or bypass grafts must be created.Rupture or threatened rupture of an abdominal aortic aneurysm requiresemergency open surgery or placement of an endovascular stent-graft.Untreated ruptured abdominal aortic aneurysms are always fatal.

Surgical repair of aneurysms <5 cm does not appear to increase survival,which may in part be due to the complications of surgery. However, suchaneurysms should be monitored with ultrasonography every 6 to 12 mo forexpansion that warrants treatment. Control of atherosclerotic riskfactors is important, and may include treatment by the methods of theinvention. If a small or moderate-sized aneurysm becomes >5.5 cm and ifrisk of perioperative complications is lower than estimated risk ofrupture, AAA surgical repair may be indicated.

Surgery typically is performed through an abdominal incision, where thesac of the aneurysm is incised and a synthetic tube is sewn in place toconnect the 2 ends of the more normal-sized aorta. Sometimes, the repairhas to include one or both of the terminal branches of the aorta (iliacarteries) that may also have become aneurysmal. Bypass of narrowed orblocked aortic branches to the kidneys or abdominal organs may also berequired. After the tube is connected at both ends, the wall of theaneurysm is wrapped around the tube. Potential complications from suchsurgery include bleeding, infection, and kidney or bowel damage.Further, because coronary artery disease is so common among patientswith AAA, a major worry is the risk of postoperative heart trouble. Asan alternative, a stent draft can be placed through an artery, e.g.femoral artery. The stent covers the entire aneurysm, and the vesselwalls eventually shrink around the stent. For example, see Blum et al.(1997) N Engl J Med. 336:13-20.

9p21 Risk. As used herein, the term “an individual carrying at least one9p21 risk factor” refers to humans in which one or more risk alleles atthe 9p21 locus are present in the genome. Such individuals have beenshown to have an increased risk of: early onset myocardial infarction,abominal aortic aneurysm, stroke, peripheral artery disease, andmyocardial infarction/coronary heart disease. This risk is independentof traditional risk factors, including diabetes, hypertension,cholesterol, and obesity. See, for example, Helgadottir et al. Science.2007; 316(5830):1491-1493; Helgadottir et al. Nat Genet. 2008;40(2):217-224; Palomaki et al. JAMA. 2010; 303(7):648-656; and Robertset al. Curr Opin Cardiol. 2008; 23:629-633, each herein specificallyincorporated by reference.

The 9p21 locus is in tight LD (linkage disequilibrium), and a number ofsingle nucleotide polymorphisms (SNP) markers have been shown to beuseful in diagnosis. Representative SNPs include without limitationrs10757278; rs3217992; rs4977574; rs1333049; rs10757274; rs2383206;rs2383207; Rs3217989; rs1333040; rs2383207; rs10116277; rs7044859;rs1292136; rs7865618; rs1333045; rs9632884; rs10757272; rs4977574;rs2891168; rs6475606; rs1333048; rs1333049; Rs1333045; etc.

Efferocytosis and Phagocytosis. The process by which professional andnonprofessional phagocytes dispose of apoptotic cells in a rapid andefficient manner. Efferocytosis involves a number of molecules,including ligands on the apoptotic cells, e.g. phosphatidylserine;receptors on the efferocyte; soluble ligand-receptor bridging molecules;and so-called “find-me” and “don't-eat-me” molecules, e.g.,lysosphospholipids and CD47, the expression of which by dying cells isaltered to attract nearby phagocytes. By clearing apoptotic cells at arelatively early stage of cell death, when the cell plasma and organellemembranes are still intact, postapoptotic, or “secondary”, necrosis isprevented. Prevention of cellular necrosis, in turn, prevents therelease of potentially damaging intracellular molecules into theextracellular milieu, including molecules that can stimulateinflammatory, proatherosclerotic and/or autoimmune responses.

The efficiency of efferocytic clearance in atherosclerotic lesions playsa key role in disease development. Efferocytosis is known to be impairedin human atherosclerotic plaque. A prominent feature of advancedatherosclerotic lesions is the necrotic core, or lipid core, which is acollection of dead and necrotic macrophages surrounded by inflammatorycells. Necrotic cores are thought to be a major feature responsible forplaque “vulnerability”, i.e., plaques capable of undergoing disruptionand triggering acute lumenal thrombosis. Plaque disruption and acutethrombosis are the events that trigger acute coronary syndromes,including myocardial infarction, unstable angina, sudden cardiac death,and stroke.

By “manipulating phagocytosis” is meant an up-regulation or adown-regulation in phagocytosis of a targeted cell, e.g. apoptotic SMC,by at least about 10%, or up to 20%, or 50%, or 70% or 80% or up toabout 90% compared to level of phagocytosis observed in absence ofintervention.

The terms “phagocytic cells” and “phagocytes” are used interchangeablyherein to refer to a cell that is capable of phagocytosis. There arethree main categories of phagocytes: macrophages, mononuclear cells(histiocytes and monocytes); polymorphonuclear leukocytes (neutrophils)and dendritic cells. However, “non-professional” cells are also known toparticipate in efferocytosis, such as neighboring SMCs in the bloodvessel wall.

“Treatment”, “treating”, “treat” and the like are used herein togenerally refer to obtaining a desired pharmacologic and/or physiologiceffect. The effect can be prophylactic in terms of completely orpartially preventing a disease or symptom thereof and/or may betherapeutic in terms of a partial or complete stabilization or cure fora disease and/or adverse effect attributable to the disease. “Treatment”as used herein covers any treatment of a disease in a mammal,particularly a human, and includes: (a) preventing the disease orsymptom from occurring in a subject which may be predisposed to thedisease or symptom but has not yet been diagnosed as having it; (b)inhibiting the disease symptom, i.e., arresting its development; or (c)relieving the disease symptom, i.e., causing regression of the diseaseor symptom. Those in need of treatment include individuals alreadydiagnosed with an aneurysm, as well as those in which the disease is tobe prevented.

The terms “recipient”, “individual”, “subject”, “host”, and “patient”,are used interchangeably herein and refer to any mammalian subject forwhom diagnosis, treatment, or therapy is desired, particularly humans.“Mammal” for purposes of treatment refers to any animal classified as amammal, including humans, domestic and farm animals, and zoo, sports, orpet animals, such as dogs, horses, cats, cows, sheep, goats, pigs, etc.Preferably, the mammal is human.

An “effective amount” is an amount sufficient to effect beneficial ordesired clinical results. An effective amount can be administered in oneor more administrations. For purposes of this invention, an effectiveamount of an EP agent is an amount that is sufficient to palliate,ameliorate, stabilize, reverse, prevent, slow or delay the progressionof the disease state, e.g. an aneurysm, by increasing phagocytosis of atarget cell.

For example, in an animal model the incidence of death in a samplepopulation due to aneurysm maybe reduced relative to a control treatedanimal by may be reduced 25%, 50%, 75%. Alternatively, treatment withthe methods of the invention may be monitored by reduction orstabilization of an existing aneurysm, for example where the size of anexisting aneurysm is stabilized over time relative to an untreatedsubject, e.g. where an increase is size over time is reduced by up toabout 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or more related to anuntreated individual. Such monitoring may be performed in a population,e.g. in a clinical trial cohort study.

In some embodiments the subject being treated has been diagnosed with ananeurysm, e.g. an aneurysm greater than the normal diameter of theaorta, which may be, for example greater than about 2 cm diameter, andmay be less than about the size of an aneurysm for which surgery isindicated, e.g. less than about 6 cm diameter, less than about 5.5 cmdiameter, less than about 5 cm diameter. Treatment may be initiated whenan aneurysm, including without limitation an aortic aneurysm, is greaterthan about 2 cm, greater than about 2.5 cm, greater than about 3 cm,greater than about 3.5 cm, greater than about 4 cm, greater than about4.5 cm, and may be less than about 6 cm, less than about 5.5 cm, lessthan about 5 cm diameter.

The term “sample” with respect to a patient encompasses blood and otherliquid samples of biological origin, solid tissue samples such as abiopsy specimen or tissue cultures or cells derived therefrom and theprogeny thereof. The definition also includes samples that have beenmanipulated in any way after their procurement, such as by treatmentwith reagents; washed; or enrichment for certain cell populations. Thedefinition also includes sample that have been enriched for particulartypes of molecules, e.g., nucleic acids, polypeptides, etc.

The terms “specific binding,” “specifically binds,” and the like, referto non-covalent or covalent preferential binding to a molecule relativeto other molecules or moieties in a solution or reaction mixture (e.g.,an antibody specifically binds to a particular polypeptide or epitoperelative to other available polypeptides; high affinity binding of aSIRPα polypeptide to CD47; etc.) In some embodiments, the affinity ofone molecule for another molecule to which it specifically binds ischaracterized by a K_(D) (dissociation constant) of 10⁻⁵ M or less(e.g., 10⁻⁶ M or less, 10⁻⁷ M or less, 10⁻⁸ M or less, 10⁻⁹ M or less,10⁻¹⁰ M or less, 10⁻¹¹ M or less, 10⁻¹² M or less, 10⁻¹³ M or less,10⁻¹⁴ M or less, 10⁻¹⁵ M or less, or 10⁻¹⁶ M or less). “Affinity” refersto the strength of binding, increased binding affinity being correlatedwith a lower K_(D).

The term “specific binding member” as used herein refers to a member ofa specific binding pair (i.e., two molecules, usually two differentmolecules, where one of the molecules, e.g., a first specific bindingmember, through non-covalent means specifically binds to the othermolecule, e.g., a second specific binding member). Suitable specificbinding members include agents that specifically bind CD47 (i.e.,anti-CD47 agents), or that otherwise block the interaction between CD47and SIRPα, agents that bind to calreticulin or its LRP receptor, etc.

The terms “polypeptide,” “peptide” and “protein” are usedinterchangeably herein to refer to a polymer of amino acid residues. Theterms also apply to amino acid polymers in which one or more amino acidresidue is an artificial chemical mimetic of a corresponding naturallyoccurring amino acid, as well as to naturally occurring amino acidpolymers and non-naturally occurring amino acid polymer.

A “variant” polypeptide means a biologically active polypeptide asdefined below having less than 100% sequence identity with a nativesequence polypeptide. Such variants include polypeptides wherein one ormore amino acid residues are added at the N- or C-terminus of, orwithin, the native sequence; from about one to forty amino acid residuesare deleted, and optionally substituted by one or more amino acidresidues; and derivatives of the above polypeptides, wherein an aminoacid residue has been covalently modified so that the resulting producthas a non-naturally occurring amino acid. Ordinarily, a biologicallyactive variant will have an amino acid sequence having at least about90% amino acid sequence identity with a native sequence polypeptide,preferably at least about 95%, more preferably at least about 99%. Thevariant polypeptides can be naturally or non-naturally glycosylated,i.e., the polypeptide has a glycosylation pattern that differs from theglycosylation pattern found in the corresponding naturally occurringprotein. The variant polypeptides can have post-translationalmodifications not found on the natural protein.

A “fusion” polypeptide is a polypeptide comprising a polypeptide orportion (e.g., one or more domains) thereof fused or bonded toheterologous polypeptide. A fusion soluble CRT protein, for example,will share at least one biological property in common with a nativesequence soluble CRT polypeptide. Examples of fusion polypeptidesinclude immunoadhesins, as described above, which combine a portion ofthe polypeptide of interest with an immunoglobulin sequence, and epitopetagged polypeptides, which comprise a soluble polypeptide of interest orportion thereof fused to a “tag polypeptide”. The tag polypeptide hasenough residues to provide an epitope against which an antibody can bemade, yet is short enough such that it does not interfere withbiological activity of the polypeptide of interest. Suitable tagpolypeptides generally have at least six amino acid residues and usuallybetween about 6-60 amino acid residues.

A “functional derivative” of a native sequence polypeptide is a compoundhaving a qualitative biological property in common with a nativesequence polypeptide. “Functional derivatives” include, but are notlimited to, fragments of a native sequence and derivatives of a nativesequence polypeptide and its fragments, provided that they have abiological activity in common with a corresponding native sequencepolypeptide. The term “derivative” encompasses both amino acid sequencevariants of polypeptide and covalent modifications thereof. For example,derivatives and fusion of soluble CRT find use as CRT mimetic molecules.

Small molecule: As used herein, the term “small molecule” refers toorganic compounds, whether naturally-occurring or artificially created(e.g., via chemical synthesis) that have relatively low molecular weightand that are not proteins, polypeptides, or nucleic acids. Typically,small molecules have a molecular weight of less than about 1500 g/mol.Also, small molecules typically have multiple carbon-carbon bonds.

The term “antibody” is used in the broadest sense and specificallycovers monoclonal antibodies (including full length monoclonalantibodies), polyclonal antibodies, multispecific antibodies (e.g.,bispecific antibodies), and antibody fragments so long as they exhibitthe desired biological activity. “Antibodies” (Abs) and“immunoglobulins” (Igs) are glycoproteins having the same structuralcharacteristics. While antibodies exhibit binding specificity to aspecific antigen, immunoglobulins include both antibodies and otherantibody-like molecules which lack antigen specificity. Polypeptides ofthe latter kind are, for example, produced at low levels by the lymphsystem and at increased levels by myelomas.

“Antibody fragment”, and all grammatical variants thereof, as usedherein are defined as a portion of an intact antibody comprising theantigen binding site or variable region of the intact antibody, whereinthe portion is free of the constant heavy chain domains (i.e. CH2, CH3,and CH4, depending on antibody isotype) of the Fc region of the intactantibody. Examples of antibody fragments include Fab, Fab′, Fab′-SH,F(ab′)2, and Fv fragments; diabodies; any antibody fragment that is apolypeptide having a primary structure consisting of one uninterruptedsequence of contiguous amino acid residues (referred to herein as a“single-chain antibody fragment” or “single chain polypeptide”),including without limitation (1) single-chain Fv (scFv) molecules (2)single chain polypeptides containing only one light chain variabledomain, or a fragment thereof that contains the three CDRs of the lightchain variable domain, without an associated heavy chain moiety (3)single chain polypeptides containing only one heavy chain variableregion, or a fragment thereof containing the three CDRs of the heavychain variable region, without an associated light chain moiety and (4)nanobodies comprising single Ig domains from non-human species or otherspecific single-domain binding modules; and multispecific or multivalentstructures formed from antibody fragments. In an antibody fragmentcomprising one or more heavy chains, the heavy chain(s) can contain anyconstant domain sequence (e.g. CH1 in the IgG isotype) found in a non-Fcregion of an intact antibody, and/or can contain any hinge regionsequence found in an intact antibody, and/or can contain a leucinezipper sequence fused to or situated in the hinge region sequence or theconstant domain sequence of the heavy chain(s).

As used in this invention, the term “epitope” means any antigenicdeterminant on an antigen to which the paratope of an antibody binds.Epitopic determinants usually consist of chemically active surfacegroupings of molecules such as amino acids or sugar side chains andusually have specific three dimensional structural characteristics, aswell as specific charge characteristics.

Cyclin-dependent kinase inhibitor 2B (CDKN2B) is also known as multipletumor suppressor 2 (MTS-2) or p15INK4B. The Genbank refseq for the humanmRNA has the accession number NM_004936 and the protein refseq has theaccession number NP_004927. This gene lies adjacent to the tumorsuppressor gene CDKN2A in a region that is frequently mutated anddeleted in a wide variety of tumors.

CDKN2B forms a complex with CDK4 or CDK6, and prevents the activation ofthe CDK kinases by cyclin D, thus the encoded protein functions as acell growth regulator that inhibits cell cycle G1 progression.

It is shown herein that decreased CDKN2B expression associated with 9p21risk alleles impairs expression of calreticulin, a ligand required foractivation of engulfment receptors on phagocytic cells. As a result,cdkn2B-deficient apoptotic bodies, e.g. apoptotic smooth muscle cells,are rendered resistant to efferocytosis and are not efficiently clearedby phagocytic cells.

Agents that activate or upregulate CDKN2B expression are known in theart, including, for example, palbociclib (see Toogood et al. (2005) JMed Chem. 48(7):2388-406); 5-aza-2′-deoxycytidine in the absence orpresence of phenylbutyrate (see Lemaire et al. (2004) Leuk Lymphoma.45(1):147-54); hypoxia-inducible-factors-1a and -2a (see Aesoey et al.(2013) Endocr Rev, Vol. 34 (03_Meeting Abstracts): SUN-303; etc. Agentsthat activate or upregulate CDKN2B can be determined by screeningmethods as known in the art.

Calreticulin. Calreticulin is a multifunctional protein of 417 aminoacids, molecular weight 48 kDa, that binds Ca²⁺ ions, rendering itinactive. The Ca²⁺ is bound with low affinity, but high capacity, andcan be released on a signal. Calreticulin can be located in storagecompartments associated with the endoplasmic reticulum, where it bindsto misfolded proteins and prevents them from being exported to the Golgiapparatus. Calreticulin is also found in the nucleus, suggesting that itmay have a role in transcription regulation. Calreticulin binds to thesynthetic peptide KLGFFKR, which is almost identical to an amino acidsequence in the DNA-binding domain of the superfamily of nuclearreceptors. The gene symbol for calreticulin is CALR, and the humansequences may be accessed at Pubmed as follows: Protein Accession#NP_004334; Nucleotide Accession #: NM_004343.

Calreticulin on the surface of apoptotic cells serves as a recognitionand clearance ligand by activating the internalization receptor LRP onthe responding phagocyte cell surface. The surface expression ofcalreticulin increases and calreticulin was redistributed duringapoptosis, possibly enhancing stimulation of LRP on the phagocyte.

The low density lipoprotein receptor-related protein (LRP) is a4,544-amino acid protein containing a single transmembrane segment, witha high degree of sequence identity to the LDL receptor. The humangenetic sequences may be accessed at Pubmed as follows: NucleotideAccession #: NM_002332.2 GI:126012561.

Agents that specifically bind to calreticulin (CRT) are of interest asagonists for enhancing the pro-phagocytic activity of CRT. CRT bindingagents useful in the methods of the invention include analogs,derivatives and fragments of the original specific binding member, e.g.Fab fragments of antibodies, etc. Calreticulin “mimetics” and “agonists”include molecules that function similarly to or potentiate CRT bybinding and activating LRP receptor. Molecules useful as CRT mimeticsinclude derivatives, variants, and biologically active fragments ofnaturally occurring CRT. Molecules useful as agonists include antibodiesand other agents that act to enhance the pro-phagocytic activity of CRT.

Fragments of soluble CRT, particularly biologically active fragmentsand/or fragments corresponding to functional domains, are of interest.Fragments of interest will typically be at least about 10 aa to at leastabout 15 aa in length, usually at least about 50 aa in length, but willusually not exceed about 142 aa in length, where the fragment will havea stretch of amino acids that is identical to CRT. A fragment “at least20 aa in length,” for example, is intended to include 20 or morecontiguous amino acids from, for example, the polypeptide encoded by acDNA for CRT. In this context “about” includes the particularly recitedvalue or a value larger or smaller by several (5, 4, 3, 2, or 1) aminoacids.

In vitro assays for calreticulin biological activity include, e.g.phagocytosis of porcine cells by human macrophages, binding to LRP, etc.A candidate agent useful as a calreticulin agonist mimetic results inthe down regulation of phagocytosis by at least about 10%, at leastabout 20%, at least about 50%, at least about 70%, at least about 80%,or up to about 90% compared to level of phagocytosis observed in absenceof candidate agent.

CD47, also known as integrin associated protein (IAP) is a 50 kDamembrane receptor that has extracellular N-terminal IgV domain, fivetransmembrane domains, and a short C-terminal intracellular tailtransmembrane, belonging to the immunoglobulin superfamily, withinteracts with integrins, most commonly integrin αvβ3, thrombospondin-1(TSP-1) and signal-regulatory protein alpha (SIRPα). The referencesequence for the human mRNA has the Genbank accession numberNM_001025079, and the protein reference sequence is NP_001768.

The CD47/SIRPα interaction leads to bidirectional signaling, resultingin different cell-to-cell responses including inhibition ofphagocytosis, stimulation of cell-cell fusion, and T-cell activation.

As used herein, the term “anti-CD47 agent” refers to any agent thatreduces the binding of CD47 (e.g., on an affected cell) to SIRPα (e.g.,on a phagocytic cell). In some embodiments the anti-CD47 agent does notinterfere or bind to the regions of CD47 that bind to thrombospondin. Insome embodiments, the anti-CD47 agent does not activate CD47 uponbinding. When CD47 is activated, a process akin to apoptosis (i.e.,programmed cell death) occurs (Manna and Frazier, Cancer Research, 64,1026-1036, Feb. 1, 2004). Thus, in some embodiments, the anti-CD47 agentdoes not directly induce apoptotic cell death of a CD47-expressing cell.

Non-limiting examples of suitable anti-CD47 reagents include a solubleSIRPα polypeptide, which may be a high affinity SIRPa polypeptide, andwhich is optionally joined to an immunoglobulin domain, e.g. an Fcregion, etc., anti-SIRPα antibodies, and anti-CD47 antibodies orantibody fragments. In some embodiments, a suitable anti-CD47 agent(e.g. an anti-CD47 antibody, a high affinity SIRPα reagent, etc.)specifically binds CD47 to reduce the binding of CD47 to SIRPα. In someembodiments, a suitable anti-CD47 agent (e.g., an anti-SIRPα antibody,etc.) specifically binds SIRPα to reduce the binding of CD47 to SIRPα. Asuitable anti-CD47 agent that binds SIRPα does not activate SIRPα (e.g.,in the SIRPα-expressing phagocytic cell).

The efficacy of a suitable anti-CD47 agent can be assessed by assayingthe agent. An agent for use in the methods of the invention willup-regulate phagocytosis by at least 10% (e.g., at least 20%, at least30%, at least 40%, at least 50%, at least 60%, at least 70%, at least80%, at least 90%, at least 100%, at least 120%, at least 140%, at least160%, at least 160%, or at least 200%) compared to phagocytosis in theabsence of the agent. Similarly, an in vitro assay for levels oftyrosine phosphorylation of SIRPα will show a decrease inphosphorylation by at least 5% (e.g., at least 10%, at least 15%, atleast 20%, at least 30%, at least 40%, at least 50%, at least 60%, atleast 70%, at least 80%, at least 90%, or 100%) compared tophosphorylation observed in absence of the candidate agent.

In one embodiment of the invention, the anti-CD47 agent, or apharmaceutical composition comprising the agent, is provided in anamount effective to detectably inhibit the binding of CD47 to SIRPαpresent on the surface of phagocytic cells. The effective amount isdetermined via empirical testing routine in the art, for example in abiological sample taken from an infected individual. The effectiveamount may vary depending on the number of cells being targeted, thelocation of the cells, and factors specific to the subject.

High affinity SIRPα reagent. In some embodiments, a subject anti-CD47agent is a “high affinity SIRPα reagent”, which includes SIRPα-derivedpolypeptides and analogs thereof. High affinity SIRPα reagents aredescribed in international application PCT/US13/21937, which is herebyspecifically incorporated by reference. High affinity SIRPα reagents arevariants of the native SIRPα protein. In some embodiments, a highaffinity SIRPα reagent is soluble, where the polypeptide lacks the SIRPαtransmembrane domain and comprises at least one amino acid changerelative to the wild-type SIRPα sequence, and wherein the amino acidchange increases the affinity of the SIRPα polypeptide binding to CD47,for example by decreasing the off-rate by at least 10-fold, at least20-fold, at least 50-fold, at least 100-fold, at least 500-fold, ormore.

A high affinity SIRPα reagent comprises the portion of SIRPα that issufficient to bind CD47 at a recognizable affinity, e.g., high affinity,which normally lies between the signal sequence and the transmembranedomain, or a fragment thereof that retains the binding activity. Thehigh affinity SIRPα reagent will usually comprise at least the d1 domainof SIRPα with modified amino acid residues to increase affinity. In someembodiments, a SIRPα variant of the present invention is a fusionprotein, e.g., fused in frame with a second polypeptide. In someembodiments, the second polypeptide is capable of increasing the size ofthe fusion protein, e.g., so that the fusion protein will not be clearedfrom the circulation rapidly. In some embodiments, the secondpolypeptide is part or whole of an immunoglobulin Fc region. In otherembodiments, the second polypeptide is any suitable polypeptide that issubstantially similar to Fc, e.g., providing increased size,multimerization domains, and/or additional binding or interaction withIg molecules.

A suitable high affinity SIRPα reagent reduces (e.g., blocks, prevents,etc.) the interaction between the native proteins SIRPα and CD47. Theamino acid changes that provide for increased affinity are localized inthe d1 domain, and thus high affinity SIRPα reagents comprise a d1domain of human SIRPα, with at least one amino acid change relative tothe wild-type sequence within the d1 domain. Such a high affinity SIRPαreagent optionally comprises additional amino acid sequences, forexample antibody Fc sequences; portions of the wild-type human SIRPαprotein other than the d1 domain, including without limitation residues150 to 374 of the native protein or fragments thereof, usually fragmentscontiguous with the d1 domain; and the like. High affinity SIRPαreagents may be monomeric or multimeric, i.e. dimer, trimer, tetramer,etc.

Anti-CD47 antibodies. In some embodiments, a subject anti-CD47 agent isan antibody that specifically binds CD47 (i.e., an anti-CD47 antibody)and reduces the interaction between CD47 on one cell (e.g., an infectedcell) and SIRPα on another cell (e.g., a phagocytic cell). In someembodiments, a suitable anti-CD47 antibody does not activate CD47 uponbinding. Non-limiting examples of suitable antibodies include clonesB6H12, 5F9, 8B6, and C3 (for example as described in InternationalPatent Publication WO 2011/143624, herein specifically incorporated byreference).

Anti-SIRPα antibodies. In some embodiments, a subject anti-CD47 agent isan antibody that specifically binds SIRPα (i.e., an anti-SIRPα antibody)and reduces the interaction between CD47 on one cell (e.g., an infectedcell) and SIRPα on another cell (e.g., a phagocytic cell). Suitableanti-SIRPα antibodies can bind SIRPα without activating or stimulatingsignaling through SIRPα because activation of SIRPα would inhibitphagocytosis. Instead, suitable anti-SIRPα antibodies facilitate thepreferential phagocytosis of infected cells over non-infected cells.Those cells that express higher levels of CD47 (e.g., infected cells)relative to other cells (non-infected cells) will be preferentiallyphagocytosed. Thus, a suitable anti-SIRPα antibody specifically bindsSIRPα without activating/stimulating enough of a signaling response toinhibit phagocytosis.

Suitable antibodies include fully human, humanized or chimeric versionsof such antibodies. Humanized antibodies are especially useful for invivo applications in humans due to their low antigenicity. Similarlycaninized, felinized, etc antibodies are especially useful forapplications in dogs, cats, and other species respectively.

Methods

Methods are provided for treating or reducing aneurysm disease byadministering an agent to an individual that increases efferocytosisand/or phagocytosis of cellular components (EP pathway activity);reducing aneurysm risk or disease. Aneurysm disease may be present in anartery of the individual, including without limitation cerebralarteries, abdominal aorta, thoracic aorta, etc. In some embodiments, theindividual is homozygous or heterozygous for a 9p21 risk allele. In someembodiments, the agent that increases activity of the EP pathwayprovides for one or more of the following activities: reduces thebinding of CD47 to SIRPα; increases or mimics the activity ofcalreticulin, including binding of calreticulin to LRP; or increasesexpression of CDKN2B. Such methods include administering to a subject inneed of treatment a therapeutically effective amount or an effectivedose of an EP pathway stimulating agent, including without limitationcombinations of the agent with another drug. Methods of administrationto the cardiovascular system are of interest, although oral formulationsmay also find use.

Effective doses of the therapeutic entity of the present invention varydepending upon many different factors, including the nature of theagent, means of administration, target site, physiological state of thepatient, whether the patient is human or an animal, other medicationsadministered, and whether treatment is prophylactic or therapeutic.Usually, the patient is a human, but nonhuman mammals may also betreated, e.g. companion animals such as dogs, cats, horses, etc.,laboratory mammals such as rabbits, mice, rats, etc., and the like.Treatment dosages can be titrated to optimize safety and efficacy.

In some embodiments, the therapeutic dosage can range from about 0.0001to 500 mg/kg, and more usually 0.01 to 100 mg/kg, of the host bodyweight. For example dosages can be 1 mg/kg body weight or 10 mg/kg bodyweight or within the range of 1-50 mg/kg. The dosage may be adjusted forthe molecular weight of the reagent. An exemplary treatment regimeentails administration daily, semi-weekly, weekly, once every two weeks,once a month, etc. In another example, treatment can be given as acontinuous infusion. Therapeutic entities of the present invention areusually administered on multiple occasions. Intervals between singledosages can be weekly, monthly or yearly. Intervals can also beirregular as indicated by measuring blood levels of the therapeuticentity in the patient. Alternatively, therapeutic entities of thepresent invention can be administered as a sustained releaseformulation, in which case less frequent administration is required.Dosage and frequency vary depending on the half-life of the polypeptidein the patient. It will be understood by one of skill in the art thatsuch guidelines will be adjusted for the molecular weight of the activeagent, e.g. in the use of polypeptide fragments, in the use of antibodyconjugates, in the use of high affinity SIRPα reagents, etc. The dosagemay also be varied for localized administration, e.g. intranasal,inhalation, etc., or for systemic administration, e.g. i.m., i.p., i.v.,and the like.

For the treatment of disease, the appropriate dosage of the agent willdepend on the severity and course of the disease, whether the agent isadministered for preventive purposes, previous therapy, the patient'sclinical history and response to the antibody, and the discretion of theattending physician. The agent is suitably administered to the patientat one time or over a series of treatments.

Suitable agents can be provided in pharmaceutical compositions suitablefor therapeutic use, e.g. for human treatment. In some embodiments,pharmaceutical compositions of the present invention include one or moretherapeutic entities of the present invention or pharmaceuticallyacceptable salts, esters or solvates thereof. In some other embodiments,the use of an efferocytosis stimulating agent includes use incombination with another therapeutic agent, e.g., drugs useful in thetreatment of atherosclerosis. Such combinations may include, withoutlimitation, statins. Statins are inhibitors of HMG-CoA reductase enzyme.These agents are described in detail; for example, mevastatin andrelated compounds as disclosed in U.S. Pat. No. 3,983,140; lovastatin(mevinolin) and related compounds as disclosed in U.S. Pat. No.4,231,938; pravastatin and related compounds as disclosed in U.S. Pat.No. 4,346,227; simvastatin and related compounds as disclosed in U.S.Pat. Nos. 4,448,784 and 4,450,171; fluvastatin and related compounds asdisclosed in U.S. Pat. No. 5,354,772; atorvastatin and related compoundsas disclosed in U.S. Pat. Nos. 4,681,893, 5,273,995 and 5,969,156; andcerivastatin and related compounds as disclosed in U.S. Pat. Nos.5,006,530 and 5,177,080. Additional agents and compounds are disclosedin U.S. Pat. Nos. 5,208,258, 5,130,306, 5,116,870, 5,049,696, RE 36,481,and RE 36,520. Statins include the salts and/or ester thereof.

Other drugs useful in combination include, for example, fibrates such asgemfibrozil, fenofibrate, etc.; niacin; zetia; bile acid sequestrants,e.g. cholestyramine, colestipol, colesevelam; lovaza, vascepa; drugs toreduce hypertension, etc.

Therapeutic formulations comprising one or more agents of the inventionare prepared for storage by mixing the agent having the desired degreeof purity with optional physiologically acceptable carriers, excipientsor stabilizers (Remington's Pharmaceutical Sciences 16th edition, Osol,A. Ed. (1980)), in the form of lyophilized formulations or aqueoussolutions. The agent composition will be formulated, dosed, andadministered in a fashion consistent with good medical practice. Factorsfor consideration in this context include the particular disorder beingtreated, the particular mammal being treated, the clinical condition ofthe individual patient, the cause of the disorder, the site of deliveryof the agent, the method of administration, the scheduling ofadministration, and other factors known to medical practitioners. The“therapeutically effective amount” of the agent to be administered willbe governed by such considerations, and is the minimum amount necessaryto treat or prevent atherosclerosis.

The agent can be administered by any suitable means, including topical,oral, parenteral, subcutaneous, intraperitoneal, intrapulmonary, andintranasal. Parenteral infusions include intramuscular, intravenous,intraarterial, intraperitoneal, intrathecal or subcutaneousadministration. In addition, the agent can be suitably administered bypulse infusion, particularly with declining doses of the agent.

The agent need not be, but is optionally formulated with one or moreagents that potentiate activity, or that otherwise increase thetherapeutic effect. These are generally used in the same dosages andwith administration routes as used hereinbefore or about from 1 to 99%of the heretofore employed dosages.

An agent is often administered as a pharmaceutical compositioncomprising an active therapeutic agent and another pharmaceuticallyacceptable excipient. The preferred form depends on the intended mode ofadministration and therapeutic application. The compositions can alsoinclude, depending on the formulation desired,pharmaceutically-acceptable, non-toxic carriers or diluents, which aredefined as vehicles commonly used to formulate pharmaceuticalcompositions for animal or human administration. The diluent is selectedso as not to affect the biological activity of the combination. Examplesof such diluents are distilled water, physiological phosphate-bufferedsaline, Ringer's solutions, dextrose solution, and Hank's solution. Inaddition, the pharmaceutical composition or formulation may also includeother carriers, adjuvants, or nontoxic, nontherapeutic, nonimmunogenicstabilizers and the like.

In still some other embodiments, pharmaceutical compositions can alsoinclude large, slowly metabolized macromolecules such as proteins,polysaccharides such as chitosan, polylactic acids, polyglycolic acidsand copolymers (such as latex functionalized Sepharose™′ agarose,cellulose, and the like), polymeric amino acids, amino acid copolymers,and lipid aggregates (such as oil droplets or liposomes).

A carrier may bear the agents in a variety of ways, including covalentbonding either directly or via a linker group, and non-covalentassociations. Suitable covalent-bond carriers include proteins such asalbumins, peptides, and polysaccharides such as aminodextran, each ofwhich have multiple sites for the attachment of moieties. A carrier mayalso bear an anti-CD47 agent by non-covalent associations, such asnon-covalent bonding or by encapsulation. The nature of the carrier canbe either soluble or insoluble for purposes of the invention. Thoseskilled in the art will know of other suitable carriers for bindinganti-CD47 agents, or will be able to ascertain such, using routineexperimentation.

Acceptable carriers, excipients, or stabilizers are non-toxic torecipients at the dosages and concentrations employed, and includebuffers such as phosphate, citrate, and other organic acids;antioxidants including ascorbic acid and methionine; preservatives (suchas octadecyidimethylbenzyl ammonium chloride; hexamethonium chloride;benzalkonium chloride, benzethonium chloride; phenol, butyl or benzylalcohol; alkyl parabens such as methyl or propyl paraben; catechol;resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecularweight (less than about 10 residues) polypeptides; proteins, such asserum albumin, gelatin, or immunoglobulins; hydrophilic polymers such aspolyvinylpyrrolidone; amino acids such as glycine, glutamine,asparagine, histidine, arginine, or lysine; monosaccharides,disaccharides, and other carbohydrates including glucose, mannose, ordextrins; chelating agents such as EDTA; sugars such as sucrose,mannitol, trehalose or sorbitol; salt-forming counter-ions such assodium; metal complexes (e.g., Zn-protein complexes); and/or non-ionicsurfactants such as TWEEN™, PLURONICS™ or polyethylene glycol (PEG).Formulations to be used for in vivo administration must be sterile. Thisis readily accomplished by filtration through sterile filtrationmembranes.

The active ingredients may also be entrapped in microcapsule prepared,for example, by coacervation techniques or by interfacialpolymerization, for example, hydroxymethylcellulose orgelatin-microcapsule and poly-(methylmethacylate) microcapsule,respectively, in colloidal drug delivery systems (for example,liposomes, albumin microspheres, microemulsions, nano-particles andnanocapsules) or in macroemulsions. Such techniques are disclosed inRemington's Pharmaceutical Sciences 16th edition, Osol, A. Ed. (1980).

Carriers and linkers specific for radionuclide agents includeradiohalogenated small molecules and chelating compounds. A radionuclidechelate may be formed from chelating compounds that include thosecontaining nitrogen and sulfur atoms as the donor atoms for binding themetal, or metal oxide, radionuclide.

Radiographic moieties for use as imaging moieties in the presentinvention include compounds and chelates with relatively large atoms,such as gold, iridium, technetium, barium, thallium, iodine, and theirisotopes. It is preferred that less toxic radiographic imaging moieties,such as iodine or iodine isotopes, be utilized in the methods of theinvention. Such moieties may be conjugated to the anti-CD47 agentthrough an acceptable chemical linker or chelation carrier. Positronemitting moieties for use in the present invention include ¹⁸F, whichcan be easily conjugated by a fluorination reaction with the agent.

Typically, compositions are prepared as injectables, either as liquidsolutions or suspensions; solid forms suitable for solution in, orsuspension in, liquid vehicles prior to injection can also be prepared.The preparation also can be emulsified or encapsulated in liposomes ormicro particles such as polylactide, polyglycolide, or copolymer forenhanced adjuvant effect, as discussed above. Langer, Science 249: 1527,1990 and Hanes, Advanced Drug Delivery Reviews 28: 97-119, 1997. Theagents of this invention can be administered in the form of a depotinjection or implant preparation which can be formulated in such amanner as to permit a sustained or pulsatile release of the activeingredient. The pharmaceutical compositions are generally formulated assterile, substantially isotonic and in full compliance with all GoodManufacturing Practice (GMP) regulations of the U.S. Food and DrugAdministration.

Toxicity of the agents can be determined by standard pharmaceuticalprocedures in cell cultures or experimental animals, e.g., bydetermining the LD₅₀ (the dose lethal to 50% of the population) or theLD₁₀₀ (the dose lethal to 100% of the population). The dose ratiobetween toxic and therapeutic effect is the therapeutic index. The dataobtained from these cell culture assays and animal studies can be usedin formulating a dosage range that is not toxic for use in human. Thedosage of the proteins described herein lies preferably within a rangeof circulating concentrations that include the effective dose withlittle or no toxicity. The dosage can vary within this range dependingupon the dosage form employed and the route of administration utilized.The exact formulation, route of administration and dosage can be chosenby the individual physician in view of the patient's condition.

Genetic Screening

In one aspect of the present invention, an individual is tested for thepresence of a 9p21 risk allele prior to treatment. Such methods comprisean analysis of genomic DNA in an individual for a 9p21 allele thatconfers an increased susceptibility to atherosclerosis and aneurysmdisease. Individuals are screened by analyzing their genomic sequence at9p21, e.g. rs10757278 or rs1333049 or another representative 9p21 SNPsequences for the presence of a predisposing allele, as compared to anormal sequence.

A number of methods are used for determining the presence of apredisposing variant in an individual. Genomic DNA is isolated from theindividual or individuals that are to be tested. DNA can be isolatedfrom any nucleated cellular source such as blood, hair shafts, saliva,mucous, biopsy, feces, etc. Methods using PCR amplification can beperformed on the DNA from a single cell, although it is convenient touse at least about 10⁵ cells. Where large amounts of DNA are available,the genomic DNA is used directly. Alternatively, the region of interestis cloned into a suitable vector and grown in sufficient quantity foranalysis, or amplified by conventional techniques. Of particularinterest is the use of the polymerase chain reaction (PCR) to amplifythe DNA that lies between two specific primers. The use of thepolymerase chain reaction is described in Saiki et al. (1985) Science239:487, and a review of current techniques may be found in McPherson etal. (2000) PCR (Basics: From Background to Bench) Springer Verlag; ISBN:0387916008. A detectable label may be included in the amplificationreaction. Suitable labels include fluorochromes, e.g. fluoresceinisothiocyanate (FITC), rhodamine, Texas Red, phycoerythrin,allophycocyanin, 6-carboxyfluorescein (6-FAM),2′,7′-dimethoxy-4′,5′-dichloro-6-carboxyfluorescein (JOE),6-carboxy-X-rhodamine (ROX),6-carboxy-2′,4′,7′,4,7-hexachlorofluorescein (HEX), 5-carboxyfluorescein(5-FAM) or N,N,N′,N′-tetramethyl-6-carboxyrhodamine (TAMRA), radioactivelabels, e.g. ³²P, ³⁵S, ³H; etc. The label may be a two stage system,where the amplified DNA is conjugated to biotin, haptens, etc. having ahigh affinity binding partner, e.g. avidin, specific antibodies, etc.,where the binding partner is conjugated to a detectable label. The labelmay be conjugated to one or both of the primers. Alternatively, the poolof nucleotides used in the amplification is labeled, so as toincorporate the label into the amplification product.

Primer pairs are selected from the genomic sequence using conventionalcriteria for selection. The primers in a pair will hybridize to oppositestrands, and will collectively flank the region of interest. The primerswill hybridize to the complementary sequence under stringent conditions,and will generally be at least about 16 nt in length, and may be 20, 25or 30 nucleotides in length. The primers will be selected to amplify thespecific region suspected of containing the predisposing mutation.Typically the length of the amplified fragment will be selected so as toallow discrimination between repeats of 3 to 7 units. Multiplexamplification may be performed in which several sets of primers arecombined in the same reaction tube, in order to analyze multiple exonssimultaneously. Each primer may be conjugated to a different label.

The exact composition of the primer sequences are not critical to theinvention, but they must hybridize to the flanking sequences understringent conditions. Criteria for selection of amplification primersare as previously discussed. To maximize the resolution of sizedifferences at the locus, it is preferable to choose a primer sequencethat is close to the SNP sequence, such that the total amplificationproduct is at least about 30, more usually at least about 50, preferablyat least about 100 or 200 nucleotides in length, which will vary withthe number of repeats that are present, to not more than about 500nucleotides in length. The number of repeats has been found to bepolymorphic, as previously described, thereby generating individualdifferences in the length of DNA that lies between the amplificationprimers. Conveniently, a detectable label is included in theamplification reaction. Multiplex amplification may be performed inwhich several sets of primers are combined in the same reaction tube.This is particularly advantageous when limited amounts of sample DNA areavailable for analysis. Conveniently, each of the sets of primers islabeled with a different fluorochrome.

After amplification, the products can be size fractionated.Fractionation may be performed by gel electrophoresis, particularlydenaturing acrylamide or agarose gels. A convenient system usesdenaturing polyacrylamide gels in combination with an automated DNAsequencer, see Hunkapillar et al. (1991) Science 254:59-74. Theautomated sequencer is particularly useful with multiplex amplificationor pooled products of separate PCR reactions. Capillary electrophoresismay also be used for fractionation. A review of capillaryelectrophoresis may be found in Landers, et al. (1993) BioTechniques14:98-111. The size of the amplification product is proportional to thenumber of repeats (n) that are present at the locus specified by theprimers. The size will be polymorphic in the population, and istherefore an allelic marker for that locus. The amplified or clonedfragment is alternatively sequenced by various high methods known in theart.

The presence of a predisposing risk allele is indicative that anindividual is at increased risk of developing atherosclerosis and maybenefit from treatment by the methods of the invention, although themethods can additionally find use in individuals without a 9p21 geneticrisk factor. The diagnosis of a disease predisposition allows theaffected individual to seek early treatment of potential lesions, and toavoid activities that increase risk for cardiovascular disease.

Drug Screening

Screening assays identify compounds that modulate the expression oractivity of proteins involved in the EP pathway, including withoutlimitation CDKN2B, calreticulin, CD47, SIRPα, etc. An EP pathwaystimulating agent can act as the basis for amelioration of aneurysm,particularly abdominal aortic aneurysm. Such compounds may include, butare not limited to peptides, antibodies, or small organic or inorganiccompounds. Methods for the identification of such compounds aredescribed below.

Cell- and animal-based systems can act as models for cardiovasculardisease and are useful in such drug screening. The animal- andcell-based models may be used to identify drugs, pharmaceuticals,therapies and interventions that are effective in treatingcardiovascular disease. In addition, such animal models may be used todetermine the LD₅₀ and the ED₅₀ in animal subjects, and such data can beused to determine the in vivo efficacy of potential cardiovasculardisease treatments. Animal-based model systems of cardiovascular diseasemay include, but are not limited to, non-recombinant and engineeredtransgenic animals. Non-recombinant, non-genetic animal models ofatherosclerosis may include, for example, pig, rabbit, or rat models inwhich the animal has been exposed to either chemical wounding throughdietary supplementation of LDL, or mechanical wounding through ballooncatheter angioplasty, for example. Additionally, animal modelsexhibiting cardiovascular disease symptoms may be engineered byutilizing, for example, smooth muscle cell marking, knockouts of CDKN2B,etc. gene sequences in conjunction with techniques for producingtransgenic animals that are well known to those of skill in the art. Forexample, target gene sequences may be introduced into, and knocked outor overexpressed in the genome of the animal of interest. Animals of anyspecies, including, but not limited to, mice, rats, rabbits, guineapigs, pigs, micro-pigs, goats, and non-human primates, e.g., baboons,monkeys, and chimpanzees may be used to generate cardiovascular diseaseanimal models.

Any technique known in the art may be used to introduce a target genetransgene into animals to produce the founder lines of transgenicanimals. Such techniques include, but are not limited to pronuclearmicroinjection (Hoppe, P. C. and Wagner, T. E., 1989, U.S. Pat. No.4,873,191); retrovirus mediated gene transfer into germ lines (Van derPutten et al., 1985, Proc. Natl. Acad. Sci., USA 82:6148-6152); genetargeting in embryonic stem cells (Thompson et al., 1989, Cell56:313-321); electroporation of embryos (Lo, 1983, Mol Cell. Biol.3:1803-1814); and sperm-mediated gene transfer (Lavitrano et al., 1989,Cell 57:717-723); etc.

Specific cell types within the animals may be analyzed and assayed forcellular phenotypes characteristic of cardiovascular disease. In thecase of monocytes, such phenotypes may include but are not limited toincreases in rates of LDL uptake, adhesion to endothelial cells,transmigration, foam cell formation, fatty streak formation, andproduction of foam cell specific products. Further, such cellularphenotypes may include a particular cell type's fingerprint pattern ofexpression as compared to known fingerprint expression profiles of theparticular cell type in animals exhibiting cardiovascular diseasesymptoms. The ability of smooth muscle cells to be taken up byphagocytes is of particular interest.

Cells that are down-regulated in CDKN2B activity can be utilized toidentify compounds that exhibit anti-cardiovascular disease activity. Inthe case of monocytes, such phenotypes may include but are not limitedto increases in rates of LDL uptake, adhesion to endothelial cells,transmigration, foam cell formation, fatty streak formation, andproduction by foam cells of growth factors such as bFGF, IGF-I, VEGF,IL-1, M-CSF, TGFβ, TGFα, TNFα, HB-EGF, PDGF, IFN-γ and GM-CSF.Transmigration rates, for example, may be measured using an in vitrosystem to quantify the number of monocytes that migrate across theendothelial monolayer and into the collagen layer of the subendothelialspace.

In vitro systems may be designed to identify compounds capable ofactivating efferocytosis. Such compounds may include, but are notlimited to, peptides made of D- and/or L-configuration amino acids,phosphopeptides, antibodies, and small organic or inorganic molecules.The principle of the assays used to identify compounds that upregulateCDKN2B or calreticulin involves preparing a reaction mixture of theprotein and a test compound under conditions and for a time sufficientto allow the two components to interact, and detecting the resultingchange in the desired biological activity. Alternatively, a simplebinding assay can be used as an initial screening method. These assayscan be conducted in a variety of ways. For example, one method toconduct such an assay would involve anchoring a protein or a testsubstance onto a solid phase and detecting complexes anchored on thesolid phase at the end of the reaction.

In a binding assay, the reaction can be performed on a solid phase or inliquid phase. In a solid phase assay, the nonimmobilized component isadded to the coated surface containing the anchored component. After thereaction is complete, unreacted components are removed under conditionssuch that any complexes formed will remain immobilized on the solidsurface. The detection of complexes anchored on the solid surface can beaccomplished in a number of ways. Where the previously nonimmobilizedcomponent is pre-labeled, the detection of label immobilized on thesurface indicates that complexes were formed. Where the previouslynonimmobilized component is not pre-labeled, an indirect label can beused to detect complexes anchored on the surface; e.g., using a labeledantibody specific for the previously nonimmobilized component (theantibody, in turn, may be directly labeled or indirectly labeled with alabeled anti-Ig antibody).

Alternatively, a binding reaction can be conducted in a liquid phase,the reaction products separated from unreacted components, and complexesdetected; e.g., using an immobilized antibody specific for target geneproduct or the test compound to anchor any complexes formed in solution,and a labeled antibody specific for the other component of the possiblecomplex to detect anchored complexes.

Cell-based systems such as those described above may be used to identifycompounds that act to ameliorate cardiovascular disease symptoms. Forexample, such cell systems may be exposed to a test compound at asufficient concentration and for a time sufficient to elicit such anamelioration of cardiovascular disease symptoms in the exposed cells.After exposure, the cells are examined to determine whether one or moreof the cardiovascular disease cellular phenotypes has been altered toresemble a more normal or more wild type, non-cardiovascular diseasephenotype.

In addition, animal-based disease systems, such as those described,above may be used to identify compounds capable of ameliorating diseasesymptoms. Such animal models may be used as test substrates for theidentification of drugs, pharmaceuticals, therapies, and interventions,which may be effective in treating disease. For example, animal modelsmay be exposed to a compound, suspected of exhibiting an ability toameliorate cardiovascular disease symptoms, at a sufficientconcentration and for a time sufficient to elicit such an ameliorationof disease symptoms in the exposed animals. The response of the animalsto the exposure may be monitored by assessing the reversal of disordersassociated with disease, for example, by counting the number ofatherosclerotic plaques and/or measuring their size before and aftertreatment.

With regard to intervention, any treatments that reverse any aspect ofcardiovascular disease symptoms should be considered as candidates forhuman disease therapeutic intervention. Dosages of test agents may bedetermined by deriving dose-response curves.

Toxicity and therapeutic efficacy of such compounds can be determined bystandard pharmaceutical procedures in cell cultures or experimentalanimals, e.g., for determining the LD₅₀ (the dose lethal to 50% of thepopulation) and the ED₅₀ (the dose therapeutically effective in 50% ofthe population). The dose ratio between toxic and therapeutic effects isthe therapeutic index and it can be expressed as the ratio LD₅₀/ED₅₀.Compounds that exhibit large therapeutic indices are preferred. Whilecompounds that exhibit toxic side effects may be used, care should betaken to design a delivery system that targets such compounds to thesite of affected tissue in order to minimize potential damage touninfected cells and, thereby, reduce side effects.

The data obtained from the cell culture assays and animal studies can beused in formulating a range of dosage for use in humans. The dosage ofsuch compounds lies preferably within a range of circulatingconcentrations that include the ED₅₀ with little or no toxicity. Thedosage may vary within this range depending upon the dosage formemployed and the route of administration utilized. For any compound usedin the method of the invention, the therapeutically effective dose canbe estimated initially from cell culture assays. A dose may beformulated in animal models to achieve a circulating plasmaconcentration range that includes the IC₅₀ (i.e., the concentration ofthe test compound which achieves a half-maximal inhibition of symptoms)as determined in cell culture. Such information can be used to moreaccurately determine useful doses in humans. Levels in plasma may bemeasured, for example, by high performance liquid chromatography.

The invention now being fully described, it will be apparent to one ofordinary skill in the art that various changes and modifications can bemade without departing from the spirit or scope of the invention.

EXPERIMENTAL

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how tomake and use the present invention, and are not intended to limit thescope of what the inventors regard as their invention nor are theyintended to represent that the experiments below are all or the onlyexperiments performed. Efforts have been made to ensure accuracy withrespect to numbers used (e.g. amounts, temperature, etc.) but someexperimental errors and deviations should be accounted for. Unlessindicated otherwise, parts are parts by weight, molecular weight isweight average molecular weight, temperature is in degrees Centigrade,and pressure is at or near atmospheric.

All publications and patent applications cited in this specification areherein incorporated by reference as if each individual publication orpatent application were specifically and individually indicated to beincorporated by reference.

The present invention has been described in terms of particularembodiments found or proposed by the present inventor to comprisepreferred modes for the practice of the invention. It will beappreciated by those of skill in the art that, in light of the presentdisclosure, numerous modifications and changes can be made in theparticular embodiments exemplified without departing from the intendedscope of the invention. For example, due to codon redundancy, changescan be made in the underlying DNA sequence without affecting the proteinsequence. Moreover, due to biological functional equivalencyconsiderations, changes can be made in protein structure withoutaffecting the biological action in kind or amount. All suchmodifications are intended to be included within the scope of theappended claims.

Example 1

Mice. Male apoE^(−/−) mice (backcrossed onto a C57BL/6 background) werebred by our laboratory as previously described and housed in a specific,pathogen-free environment. Standard sterilized laboratory diet and waterwere available ad libitum. At Day 0 the animals were initiated on a highfat Western diet (21% anhydrous milk fat, 19% casein and 0.15%cholesterol, Dyets no. 101511) for the ensuing weeks.

AngII Infusion. Mice (8 to 10 weeks old) were implanted with minipumpsthat delivered AngII subcutaneously at a dose of 1000 ng/kg⁻¹/min⁻¹, asdescribed previously (see Daugherty et al. (1999) Ann N Y Acad Sci. 892:108-118.

Antibodies. Rat IgG2a monoclonal antibody miap301 (see Jiang et al.(1999) J Biol Chem. 274(2):559-62) reacts with mouse CD47. Normal ratIgG was used as a control. The antibody was injected into the animals at200 μg/day i.p. with the schedule shown in FIG. 1.

Tissue. Anesthetized mice were cut open ventrally. Left cardiacventricles were perfused with phosphate-buffered saline (20 mL) underphysiologic pressure with an exit through the severed right atria.Suprarenal regions of abdominal aorta were identified between the lastpair of intercostal arteries and the right renal branch. The mesentericand renal branches and the aorta distal to the right renal branch wereligated with silk sutures, and the suprarenal aorta was harvested. Thisportion of aorta, measuring ≈5 mm in length, was infused with ≈0.3 mL ofOCT compound with a 21-gauge needle to attain full distension. Thoracicaortas between the left subclavian artery and the last pair ofintercostal arteries were also harvested. The orientation of aortas wasnoted, and tissues were frozen immediately.

Pathology and Immunocytochemistry. Aortas were obtained at selectedintervals after the initiation of AngII infusions and antibodytreatment, and were sectioned longitudinally or by cross sections (7 μmthick). For characterization of cross sections, aortic sections werecollected serially from the proximal to the distal aorta. Histology wasdetermined in sections that were taken at intervals of 200 μm. Forlongitudinal examination of tissues, 7-μm sections were also placed at200-μm intervals on slides. Standard histologic staining was performed.

Immunocytochemical staining was performed to identify macrophages (MACS)and smooth muscle (anti-smooth muscle actin (α-SMA)). At least 2 slides,containing ≈15 tissue sections, from each animal were examined for eachcell type. A peroxidase-based ABC system and the red chromogen AEC wereused to detect the antigen-antibody reaction. Controls includedisotype-matched antibodies and nonimmune sera.

Results

At day 30 the mortality for the control IgG group was 25%, 3 out of 12.All had an aortic dissection. The anti-CD47 treated group had amortality rate of 16.6% (2 out of 12), and one animal had an aorticdissection.

The dissected aorta of the test animals from the control group (FIG. 2)and the anti-CD47 treated group (FIG. 3) show the differences inaneurysm size and severity, which data is summarized in FIG. 4.

1. A method of treating a subject for aneurysm disease, the methodcomprising: administering to a subject that has been diagnosed with anaortic aneurysm, an effective dose of a high affinity SIRPa reagent thatspecifically binds to CD47 and reduces the binding of CD47 on anapoptotic cell to signal regulatory protein α (SIRPα) on a phagocyticcell and thereby increases the efferocytosis and/or phagocytosis ofcomponents of a diseased vessel wall; thereby reducing or inhibitingsymptoms of aneurysm. 2-4. (canceled)
 5. The method of claim 1, whereinthe subject is a human. 6-7. (canceled)
 8. The method of claim 1,wherein the aneurysm is from 2 to 6 cm. diameter. 9-20. (canceled) 21.The method of claim 1, wherein the high affinity SIRPa reagent is avariant of native human SIRPα, where the polypeptide lacks the SIRPαtransmembrane domain and comprises at least one amino acid changerelative to the wild-type SIRPα sequence, and wherein the amino acidchange increases the affinity of the SIRPα polypeptide binding to CD47.22. The method of claim 21, wherein the SIRPα variant is fused to animmunoglobulin Fc sequence.
 23. The method of claim 22, wherein theSIRPa variant is a dimer multimerized by the Fc sequence.